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This study will evaluate the safety and effectiveness of treating patients with severe aplastic anemia (SAA) or myelopdysplastic syndrome (MDS) with both peripheral blood stem cells from a family member and umbilical cord blood stem cells from an unrelated donor.

Patients with SAA or MDS for whom other treatments have failed or are not available may be eligible for this study. Candidates may not have a tissue-matched sibling or matched unrelated donor and must have a family member who is a partial tissue type match.

Participants undergo the following tests and procedures:

Insertion of a central intravenous (IV) line (plastic tube) into a large vein. The tube is used for giving the donated stem cells and antibiotics and other medicines, for transfusions of red blood cells and platelets, and for collecting blood samples.

Preparatory chemotherapy (fludarabine, cyclophosphamide and anti-thymocyte globulin) and total body irradiation to suppress immunity and prevent rejection of the donated cells.

Infusion of the donated stem cells and umbilical cord cells.

Immune suppression with the drugs tacrolimus, mycophenolate mofetil and prednisone to prevent rejection of the donated cells and to prevent graft-versus-host disease (GVHD), a complication of stem cell transplants in which the donor s immune cells destroy the patient s healthy tissues.

The average hospital stay after stem cell transplantation is 3 to 4 weeks. Patients return for frequent follow-up visits for the first 2 to 4 months after transplantation. Once the patient returns home, his or her referring physician is asked to send results of any laboratory testing to the NIH researchers at least every 3 months for the first 3 years and annually thereafter. Patient follow-up visits are scheduled at NIH at 1, 2, 3, 4 and 5 years after transplantation to monitor for signs of disease or post-transplantation complications, such as infection or GVHD. After 5 years, participants are offered the opportunity to enroll in NHLBI s long-term evaluation and follow-up care protocol.

Detailed Description

Severe aplastic anemia (SAA) and myelodysplastic syndrome (MDS) are life-threatening bone marrow disorders. For SAA patients, long term survival can be achieved with immunosuppressive treatment. However, of those patients treated with immunosuppressive therapy, one quarter to one third will not respond, and about 50 percent of responders will relapse.

Allogeneic bone marrow transplantation from either HLA-matched sibling or matched unrelated donor cures about 70 percent of patients with SAA and 30-60 percent of patients with MDS. Unfortunately, most patients with these disorders are not suitable candidates for hematopoietic stem cell transplantation (HSCT) due to advanced age or lack of a histocompatible donor. For such patients, transplantation using unrelated cord blood (UCB) has been shown to be a reasonable alternative transplant strategy. The advantage to UCB transplant is the ease and rapidity of availability, requirement of less than perfect HLA match, and lower rates of graft versus host disease compared to mismatched bone marrow or peripheral blood stem cell transplants. The major disadvantage of UCB transplantation in adults is the limited number of nucleated cells contained within the cord unit resulting in prolonged neutropenia and failure of engraftment which contributes to infection and transplant related mortality (TRM). In order to harness the advantage of UCB availability and to overcome the disadvantage of delayed neutrophil recovery, we propose to test whether co-administration of unrelated umbilical cord blood and a relatively low number of highly purified haploidentical peripheral blood CD34+ cells from a related donor might promote rapid engraftment and reduce TRM secondary to prolonged neutropenia associated with conventional UCBT.

This research protocol is therefore designed to evaluate the safety and effectiveness of co-infusion of unrelated umbilical cord blood and haploidentical CD34 plus cells from a related donor following nonmyeloablative conditioning for neutropenic patients with SAA or MDS with refactory anemia (RA) that has proven to be refractory to medical therapy. Subjects will receive a novel non-myeloablative immunosuppressive conditioning regimen of cyclophosphamide, fludarabine, horse ATG and one dose of total body irradiation (200cGy) followed by an infusion of the allografts. The haploidentical stem cell product will be T-cell depleted and enriched for CD34 plus cells using the Miltenyi CliniMacs system. To reduce TRM secondary to prolonged neutropenia associated with conventional UCB transplantation, haploidentical CD34+ stem cells will be co-infused with a single UCB unit (serologically matched at greater than or equal to 4/6 HLA loci).

The primary endpoint is donor engraftment by day 42 (defined as an ANC of greater than 500 from either the haplo donor, the cord, or both combined). Secondary endpoints will include standard transplant outcome variables such as non-hematological toxicities, incidence and severity of acute and chronic GVHD, and relapse of disease. We will also evaluate ANC recovery (ANC greater than 500 cells/microl) at day 22, and 100 day and 200 day treatment related mortality (TRM) of this novel transplant approach. Health related quality of life will also be assessed pre-transplant 30 and 100 days poste transplant, and every 6 months until 5 years post transplant.

Intolerance of or failure to respond standard immunosuppressive therapy.

Availability of at least one HLA-haploidentical (i.e. greater than or equal to 5/10 and less than or equal to 8/10 HLA match) related donor (HLA-A, B, C, DR, and DO loci) who is available to donate CD34+ cells (4-75 years old).

Availability of at least one 4/6 HLA-matched (HLA-A, B, and DR loci) cord blood unit from the National Marrow Donor Program (NMDP). The cord blood unit must contain a minimum TNC (prior to thawing) of at least 1.5 x 10(7) cells per kilogram of recipient body weight with the following exception: if the minimum criterion of TNC is not met the cord unit must contain at least 1.7 x 10(5) CD34 plus cells/kg (prior to thawing).

Ages 4-55 years inclusive.

Ability to comprehend the investigational nature of the study and provide informed consent. The procedure will be explained to subjects aged 4-17 years with formal consent being obtained from parents or legal guardian.

Telomere Length Testing

In patients where a suspicion for a familial bone marrow failiure syndromes (BMFS) exists, TERC and TERT mutation testing will be performed on protocol 04-H-0012 or performed elsewhere prior to enrolling on 04-H-0012.

EXCLUSION CRITERIA - RECIPIENT:

Availability of an HLA identical or 9/10 HLA matched(HLA A, B, C, DR, and DO loci-relative to serve as a stem cell donor.

The patient is deemed to be a candidate for a 6/6 HLA matched unrelated stem cell transplant (availability of a donor and resources required for such a transplant).

ECOG performance status of 2 or more.

Major anticipated illness or organ failure incompatible with survival from transplant

Severe psychiatric illness. Mental deficiency sufficiently severe as to make compliance with the transplant treatment unlikely and making informed consent impossible.

Positive pregnancy test for women of childbearing age.

HIV positive

Diagnosis of Fanconi's anemia or dyskeratosis congenita.

Diffusion capacity of carbon monoxide (DLCO) less than 40 percent predicted (patients under the age of 10 may be excluded from this criterion if they have difficulty performing the test correctly and thus are unable to have their DLCO assessed).

Left ventricular ejection fraction less than 40 percent (evaluated by ECHO) or less than 30 percent (evaluated by MUGA)

Transaminases greater than 5x upper limit of normal (when transaminases are elevated, the subject may be excluded at the discretion of the PI).

HLA mismatched family donor (greater than or equal to 5/10 and less than or eqhal to 8/10 HLA matched (HLA-A, B, C, DR and DO loci) who is available to donate CD34+ cells.

Ages 4-75 inclusive

Weight greater than or equal to 15 kg.

For adults: Ability to comprehend the investigational nature of the study and provide informed consent. For minors: Written informed consent from one parent or guardian who is not the recipient of the transplant and informed assent: The process will be explained to the minor on a level of complexity appropriate for their age and ability to comprehend.

If there is a suspicion of familial BMFS in the recipient, then the donor must have undergone genetic testing for genes associated with BMFS - performed at a CLIA-certified laboratory, prior to enrollin in this protocol.

EXCLUSION CRITERIA RELATED DONOR (ANY OF THE FOLLOWING):

Pregnant or breastfeeding.

A pediatric haploidentical donor will be excluded if a suitable adult haploidentical donor is available.